Semiconductor assembly having T-shaped interconnection and method of manufacturing the same

ABSTRACT

The present disclosure provides a semiconductor assembly and method of manufacturing the same. The semiconductor assembly includes a semiconductor device, a bulk semiconductor, a passivation layer, at least one conductive plug, a plurality of protective liners, and a plurality of isolation liners. The bulk semiconductor is disposed over the semiconductor device. The passivation layer covers the bulk semiconductor. The conductive plug comprises a first block disposed in the passivation layer and a second block disposed between the first block and the conductive pad, wherein portions of peripheries of the first and second blocks of the conductive plug are surrounded by the protective liners and the isolation liners.

TECHNICAL FIELD

The present disclosure relates to a semiconductor assembly and a methodof manufacturing the same, and more particularly to a semiconductorassembly having T-shaped interconnection and a method of manufacturingthe same.

DISCUSSION OF THE BACKGROUND

Since the invention of integrated circuits, the semiconductor industryhas experienced continuous rapid growth due to constant improvement inthe integration density of various electronic components (i.e.,transistors, diodes, resistors, capacitors, etc.). For the most part,this improvement in integration density has come from repeatedreductions in minimum feature size, allowing more components to beintegrated into a given chip area.

These integration improvements are essentially two-dimensional (2D) innature, in that the volume occupied by the integrated components isessentially on the surface of the semiconductor wafer. Dramaticimprovements in lithography have resulted in considerable improvementsin 2D integrated circuit formation. However, due to the reduced size ofthe component, the contact area between conductive pads of theintegrated components and bumps is decreased, such that delamination ofthe bumps and the conductive pad may easily occur, thereby adverselyaffecting the electrical performance and reliability of thesemiconductor device.

This Discussion of the Background section is provided for backgroundinformation only. The statements in this Discussion of the Backgroundare not an admission that the subject matter disclosed in thisDiscussion of the Background section constitute prior art to the presentdisclosure, and no part of this Discussion of the Background section maybe used as an admission that any part of this application, includingthis Discussion of the Background section, constitutes prior art to thepresent disclosure.

SUMMARY

One aspect of the present disclosure provides a semiconductor assembly.The semiconductor assembly includes a semiconductor device, a bulksemiconductor, a passivation layer, at least one conductive plug, aplurality of protective liners, and a plurality of isolation liners. Thesemiconductor device includes at least one conductive pad. Thesemiconductor wafer is disposed over the semiconductor device. Thepassivation layer covers the semiconductor wafer. The conductive plugincludes a first block disposed in the passivation layer and a secondblock disposed between the first block and the conductive pad. Portionsof peripheries of the first and second blocks of the conductive plug aresurrounded by the plurality of protective liners. The plurality ofisolation liners are disposed over portions of the peripheries of thefirst and second blocks of the conductive plug.

In some embodiments, the first block has a first width, and the secondblock has a second width less than the first width.

In some embodiments, the first and second blocks are symmetric withrespect to a central axis C.

In some embodiments, the conductive plug is surrounded by a diffusionbarrier film.

In some embodiments, the semiconductor assembly further includes adielectric layer disposed between the semiconductor device and the bulksemiconductor.

In some embodiments, at least one of the isolation liners includes avertical segment attached to the protective liners and a horizontalsegment connecting lower ends of the vertical segment to the conductiveplug.

In some embodiments, the protective liners are interposed between thevertical segments of the isolation liners and the conductive plug.

In some embodiments, the protective liners and the isolation linersseparate the conductive material from the bulk semiconductor.

In some embodiments, wherein the protective liners and the isolationliners are not in contact with the conductive pad.

Another aspect of the present disclosure provides a method ofmanufacturing a semiconductor assembly. The semiconductor assemblyincludes steps of bonding a bulk semiconductor to a semiconductor devicevia a dielectric layer; depositing a passivation layer on the bulksemiconductor; creating at least one recess in the passivation layer;creating at least one trench penetrating through the passivation layerand the bulk semiconductor and extending into the dielectric layer,wherein the trench is in communication with the recess; forming aplurality of isolation liners and a plurality of protective liners oninner walls of the bulk semiconductor, the dielectric layer and theportion of the passivation layer exposed by the recess and the trench;removing a portion of the dielectric layer below the trench to expose atleast one conductive pad of the semiconductor device; and depositing aconductive material in the trench and the recess until the trench andthe recess are filled.

In some embodiments, the method further includes a step of depositing adiffusion barrier film on the conductive pad, the isolation liners, theprotective liners, and portions of the dielectric layer and thepassivation layer exposed through the protective liners prior to thedeposition of the conductive material.

In some embodiments, the diffusion barrier film has a topology followingthe topology of the isolation liners, the protective liners, theportions of the passivation layer exposed by the recess, and theportions of the dielectric layer not covered by the isolation liners andthe protective liners.

In some embodiments, the formation of the isolation liners and theprotective liners includes steps of depositing an isolation film on thepassivation layer and in the recess and the trench; depositing aprotective film on the isolation film; removing horizontal portions ofthe protective film to form the protective liners; and removing portionsof the isolation film not covered by the protective liners.

In some embodiments, portions of the passivation layer not covered bythe isolation liners are removed during the removal of the portion ofthe portion of the dielectric layer below the trench.

In some embodiments, the portion of the dielectric layer below thetrench is removed during the removal of the portion of the isolationfilm not cover by the diffusion barrier liners.

In some embodiments, the isolation film has a topology following thetopology of the bulk semiconductor, the dielectric layer, and theportions of the passivation layer exposed by the recess and the trench.

In some embodiments, the bonding of the bulk semiconductor and thesemiconductor device includes steps of depositing dielectric films onthe semiconductor device and the bulk semiconductor; mounting thesemiconductor device on the bulk semiconductor so that the dielectricfilms are in contact; and performing an anneal process to fuse thedielectric films, thereby forming the dielectric layer.

In some embodiments, after the formation of the trench, a thickness ofthe dielectric layer below the trench is less than half of a thicknessof the dielectric layer connecting the bulk semiconductor to thesemiconductor device.

In some embodiments, the conductive pad has a first width, the recesshas a second width less than the first width, and the trench has a thirdwidth less than the first and second widths.

In some embodiments, the method further includes a step of performing agrinding process to thin the bulk semiconductor prior to the depositionof the passivation layer.

In some embodiments, the method further includes steps of performing aplanarizing process to remove a portion of the conductive materialoverflowing the recess; and forming at least one bump on the conductivematerial after the planarizing process.

With the above-mentioned configurations of the semiconductor assembly,the footprint of the conductive plug exposed through the passivationlayer is increased, thereby reducing the difficulty of bonding a bump onthe conductive plug.

The foregoing has outlined rather broadly the features and technicaladvantages of the present disclosure in order that the detaileddescription of the disclosure that follows may be better understood.Additional features and technical advantages of the disclosure aredescribed hereinafter, and form the subject of the claims of thedisclosure. It should be appreciated by those skilled in the art thatthe concepts and specific embodiments disclosed may be utilized as abasis for modifying or designing other structures, or processes, forcarrying out the purposes of the present disclosure. It should also berealized by those skilled in the art that such equivalent constructionsdo not depart from the spirit or scope of the disclosure as set forth inthe appended claims.

BRIEF DESCRIPTION OF THE DRAWINGS

A more complete understanding of the present disclosure may be derivedby referring to the detailed description and claims. The disclosureshould also be understood to be coupled to the figures' referencenumbers, which refer to similar elements throughout the description.

FIG. 1 is a cross-sectional view of an electronic system in accordancewith some embodiments of the present disclosure.

FIG. 2 is a flow diagram illustrating a method of manufacturing asemiconductor assembly in accordance with some embodiments of thepresent disclosure.

FIGS. 3 through 20 illustrate cross-sectional views of intermediatestages in the formation of a semiconductor assembly in accordance withsome embodiments of the present disclosure.

DETAILED DESCRIPTION

Embodiments, or examples, of the disclosure illustrated in the drawingsare now described using specific language. It shall be understood thatno limitation of the scope of the disclosure is hereby intended. Anyalteration or modification of the described embodiments, and any furtherapplications of principles described in this document, are to beconsidered as normally occurring to one of ordinary skill in the art towhich the disclosure relates. Reference numerals may be repeatedthroughout the embodiments, but this does not necessarily mean thatfeature(s) of one embodiment apply to another embodiment, even if theyshare the same reference numeral.

It shall be understood that, although the terms first, second, third,etc. may be used herein to describe various elements, components,regions, layers or sections, these elements, components, regions, layersor sections are not limited by these terms. Rather, these terms aremerely used to distinguish one element, component, region, layer orsection from another element, component, region, layer or section. Thus,a first element, component, region, layer or section discussed belowcould be termed a second element, component, region, layer or sectionwithout departing from the teachings of the present inventive concept.

The terminology used herein is for the purpose of describing particularexample embodiments only and is not intended to be limiting to thepresent inventive concept. As used herein, the singular forms “a,” “an”and “the” are intended to include the plural forms as well, unless thecontext clearly indicates otherwise. It shall be understood that theterms “comprises” and “comprising,” when used in this specification,point out the presence of stated features, integers, steps, operations,elements, or components, but do not preclude the presence or addition ofone or more other features, integers, steps, operations, elements,components, or groups thereof.

FIG. 1 is a cross-sectional view of an electronic system 20 inaccordance with some embodiments of the present disclosure. Referring toFIG. 1, the electronic system 20 includes a semiconductor assembly 10and an external device 22 electrically coupled to the semiconductorassembly 10 The semiconductor assembly 10 includes a semiconductordevice 110, a bulk semiconductor 124 bonded to the semiconductor device110 via a dielectric layer 136, a passivation layer 146 covering thebulk semiconductor 124, and at least one conductive plug 192 penetratingthrough the dielectric layer 136, the bulk semiconductor 124 and thepassivation layer 146, wherein the conductive plug 192 contacts at leastone conductive pad 114 of the semiconductor device 110. Thesemiconductor device 110 further includes a substrate 112 and aninsulative layer 116 covering the substrate 112, wherein the conductivepad 114 is surrounded by the insulating layer 116.

The conductive plug 192 includes a first block 1922 disposed in thepassivation layer 146 and a second block 1924 penetrating through thebulk semiconductor 124 and the dielectric layer 136, wherein the secondblock 1924 is connected to the first block 1922 in the passivation layer146. In other words, the second block 1924 is disposed between the firstblock 1922 and the conductive pad 114. The first block 1922 and thesecond block 1924 of the conductive plug 192 can be integrally formed.The first block 1922 of the conductive plug 192 has a width W1, thesecond block 1924 of the conductive plug 192 has a width W2 less thanthe width W1. The conductive pad 114 of the semiconductor device 110 hasa width W3 less than the width W1. In some embodiments, the second block1924 of the conductive plug 192 has the width W2 less than the width W3to reduce the manifesting cost. In some embodiments, the conductive plug192 includes aluminum or aluminum alloys. In alternative embodiments,the conductive plug 192 can include copper or copper alloys, which havelower resistance than aluminum.

The semiconductor assembly 10 further includes a plurality of isolationliners 162, and a plurality of protective liners 172 disposed overportions of peripheries of the first and second blocks 1922 and 1924 ofthe conductive plug 192. The isolation liners 162 and the protectiveliners 172, penetrating through the bulk semiconductor 124 and extendinginto the dielectric layer 136. The isolation liners 162 and theprotective liners 172 are not in contact with the conductive pad 114.The isolation liners 162 and the protective lines 172 can separate theconductive plug 192 from the bulk semiconductor 124, thereby preventingthe metal containing in the conductive plug 192 from diffusing into thebulk semiconductor 124.

The isolation liners 162 include a plurality of vertical segments 1622surrounding the protective liners 172 and a plurality of horizontalsegments 1624 connecting lower ends of the vertical segments 1622 to theconductive plug 192. The protective liners 172 are interposed betweenthe vertical segments 1622 of the isolation liners 162 and theconductive plug 192. The vertical and horizontal segments 1622 and 1624of the isolation liners 162 have a substantially uniform thickness. Inaddition, the vertical and horizontal segments 1622 and 1624 of theisolation liners 162 are integrally formed. The dielectric layer 136,the passivation layer 146 and the isolation liners 162 can be formedusing the same material, but the present disclosure is not limitedthereto. By way of example, the dielectric layer 136, the passivationlayer 146 and the isolation liners 162 include oxide-based material. Theprotective lines 172, having a substantially uniform thickness, caninclude refractory metals (such as tantalum and titanium).

The semiconductor assembly 10 can further include a diffusion barrierfilm 182 disposed between the protective liners 172 and the conductiveplug 192, between the conductive pad 114 and the second block 1924 ofthe conductive plug 192, between the dielectric layer 136 and the secondblock 1924 of the conductive plug 192, and between the passivation layer146 and the first block 1922 of the conductive plug 192. In other words,the conductive plug 192 is surrounded by the diffusion barrier film 182having a substantially uniform thickness. The diffusion barrier film 182includes refractory metals. In some embodiments, the diffusion barrierfilm 182 is function as an adhesive layer to prevent the conductive plug192 from flaking or spalling from the dielectric layer 136 and thepassivation layer 146. In some embodiments, the protective liners 172and the diffusion barrier film 182 can include the same refractorymetal. By way of example, the protective liners 172 can be made oftitanium, and the diffusion barrier film 182 can be made of titaniumnitride.

The semiconductor assembly 10 can also include a bump 200 physically andelectrically connected to the diffusion barrier film 182 and the firstblock 1922 of the conductive plug 192. In the present disclosure, thefirst block 1922 of the conductive plug 192 having the width W1 greaterthan that of the conductive pad 114 of the semiconductor device 110 mayincrease the contact area and adhesion strength between the conductiveplug 192 and the bump 200, such that the detachment or delamination ofthe bump 200 may be prevented.

The diffusion barrier film 182 and the conductive plug 192 serve as anelectrical interconnection between the conductive pad 114 and the bumps200. The bumps 200 serve as input/output (I/O) connections toelectrically connect the semiconductor assembly 10 to the externaldevice 22 including a central processing unit (CPU), a graphicsprocessing unit (GPU). In some embodiments, the bump 200 is in contactwith the vertical portion 1622 of the isolation liner 162 and theprotective liner 172 over the first block 1922 of the conductive plug192. In some embodiments, the bump 200 may cover a portion of thepassivation layer 146.

FIG. 2 is a flow diagram illustrating a method 300 of manufacturing asemiconductor assembly 10 in accordance with some embodiments of thepresent disclosure, and FIGS. 3 through 20 illustrate cross-sectionalviews of intermediate stages in the formation of the semiconductorassembly 10 in accordance with some embodiments of the presentdisclosure. The stages shown in FIGS. 3 to 20 are also illustratedschematically in the flow diagram in FIG. 2. In the followingdiscussion, the fabrication stages shown in FIGS. 3 to 20 are discussedin reference to the process steps shown in FIG. 2.

Referring to FIG. 3, a semiconductor device 110 and a bulk semiconductor120 are provided and dielectric films 132 and 134 are formed on thesemiconductor device 110 and the bulk semiconductor 120, respectively,according to a step S302 in FIG. 3. The dielectric film 132 is disposedto cover at least one conductive pad 114 disposed over a substrate 112and surrounded by an insulative layer 116 of the semiconductor device110.

The substrate 112 of the semiconductor device 110 can include asemiconductor wafer 1122 and one or more main components 1124 disposedin or on the semiconductor wafer 1122. The semiconductor wafer 1122 andthe bulk semiconductor 120 can be made of silicon. Alternatively oradditionally, the semiconductor wafer 1122 and bulk semiconductor 120may include other elementary semiconductor materials such as germanium.In some embodiments, the semiconductor wafer 1122 and bulk semiconductor120 are made of a compound semiconductor such as silicon carbide,gallium arsenic, indium arsenide, or indium phosphide. In someembodiments, the semiconductor wafer 1122 and bulk semiconductor 120 aremade of an alloy semiconductor such as silicon germanium, silicongermanium carbide, gallium arsenic phosphide, or gallium indiumphosphide. In some embodiments, the semiconductor wafer 1122 can includean epitaxial layer. For example, the semiconductor wafer 1122 has anepitaxial layer overlying a bulk semiconductor.

The semiconductor wafer 1122 may be formed with various doped regions(not shown) doped with p-type dopants, such as boron, and/or n-typedopants, such as phosphorus or arsenic. In some embodiments, isolationfeatures (not shown), such as shallow trench isolation (STI) features orlocal oxidation of silicon (LOCOS) features, can be introduced in thesemiconductor wafer 1122 to define and isolate various main components1124 in the semiconductor wafer 1122. The main components 1124 can beelectrically connected to the conductive pad 114 through conductivefeatures (not shown) buried in the insulative layer 116 and formed usingthe well-known damascene processes. The main components 1124 may includeactive components, such as transistors and/or diodes, and passivecomponents, such as capacitors, resistors or the like. The maincomponents 1124 are formed using various processes including deposition,etching, implantation, photolithography, annealing, and/or otherapplicable processes. In addition, the main components 1124 mayinterconnect with one another (via the conductive pad 114 and theconductive features) to form, for example, a logic device, a memorydevice, an input/output device, a system-on-chip device, anothersuitable type of device, or a combination thereof. In some embodiments,the main components 1124 may be formed in the semiconductor wafer 1122during front-end-of-line (FEOL) processes. The conductive pad 114 andthe insulative layer 116 may be formed over the semiconductor wafer 1122during back-end-of-line (BEOL) process.

The dielectric film 132 fully covers the conductive pad 114 and theinsulative layer 116. The dielectric film 132 is formed by depositing adielectric material, including oxide-based material, on thesemiconductor device 110 using a chemical vapor deposition (CVD)process, for example. The dielectric film 134 is formed on the entirefront surface 1202 of the bulk semiconductor 120. The dielectric film134, including oxide-based material, can be a deposition layer formedusing a CVD process or an oxidized layer formed using a thermaloxidation process, wherein the thermally-grown oxides can include ahigher level of purity than the deposited oxides.

Referring to FIG. 4, the bulk semiconductor 120 is flipped upside down,such that the dielectric films 132 and 134 can face and be aligned withone another. In some embodiments, planarizing processes can beoptionally performed on the dielectric films 132 and 134 prior to thealignment of the semiconductor device 110 and the bulk semiconductor 120to yield an acceptably flat topology.

Referring to FIG. 5, the bulk semiconductor 120 is bonded to thesemiconductor device 110 according to a step S304 in FIG. 2. After thebonding of the semiconductor device 110 to the bulk semiconductor 120,the dielectric film 132 on the semiconductor device 110 is in directcontact with the dielectric film 134 on the bulk semiconductor 120.After surfaces of the dielectric films 132 and 134 are brought intocontact, heat and force are applied to fuse the dielectric films 132 and134, thus forming a dielectric layer 130. In some embodiments, thestrength of the fusion bonding between the dielectric films 132 and 134may be increased by exposing the semiconductor device 110 and the bulksemiconductor 120 coated with the dielectric films 132 and 134,respectively, to an anneal process.

In addition, the dielectric film 134 coated on the bulk semiconductor120 has a first thickness T1, and the dielectric film 132 covering thesemiconductor device 110 has a second thickness T2 greater than thefirst thickness T1, thereby mitigating stress applied to thesemiconductor device 110 during the fusing of the dielectric films 132and 134.

Referring to FIGS. 5 and 6, a thinning process is performed on the bulksemiconductor 120 to decrease a thickness thereof according to a stepS306 in FIG. 2. The bulk semiconductor 120 shown in FIG. 5 is thinned toreduce processing time for forming at least one conductive plug, asdescribed below. In FIG. 6, the dotted line on the thinned bulksemiconductor 122 indicates an original thickness of the bulksemiconductor 120. The thinning process can be implemented usingsuitable techniques such as grinding, polishing and/or chemical etching.

Referring to FIG. 7, a passivation layer 140 is deposited on the thinnedbulk semiconductor 122 according to a step S308 in FIG. 2. Thepassivation layer 140 can be formed by depositing a dielectric materialon a surface 1222 of the thinned bulk semiconductor 122. The passivationlayer 140, including silicon-containing materials such as silicondioxide or silicon nitride, may be formed using a spin-coating process,a CVD process, or another suitable process that can form a dielectricmaterial. In some embodiments, a planarizing process can be optionallyperformed after the deposition of the dielectric material to yield anacceptably flat topology. In some embodiments, the passivation layer 140can have a uniform thickness.

Referring to FIG. 8, a first photoresist mask 210, including at leastone opening 212, is provided on the passivation layer 140. The firstphotoresist mask 210 is formed by steps including (1) conformallycoating a photosensitive material on the passivation layer 140, (2)exposing portions of the photosensitive material to radiation (notshown), (3) performing a post-exposure baking process, and (4)developing the photosensitive material, thereby forming the opening 212to expose a portion of the passivation layer 140. The portion of thepassivation layer 140 over the conductive pad 114 is exposed through thefirst photoresist mask 210.

Referring to FIGS. 8 and 9, a recess 144 is created in the passivationlayer 140 according to a step S310 in FIG. 2. The recess 144 is formedby removing a portion of the passivation layer 140 not covered by thephotoresist mask 210. The portion of the passivation layer 140 isremoved using a dry etching process, an anisotropic wet etching process,or any other suitable anisotropic process, so that the width of theopening 212 is maintained in the recess 144.

Referring to FIG. 9, a portion of the remaining passivation layer 142,that is not etched, has a thickness T3, and the recess 144 has a depth Dless than the thickness T3. In some embodiments, the depth D is greaterthan half of the thickness T3. In some embodiments, the conductive pad114 has a width W3, and the recess 144, over the conductive pad 114, hasa width W4 greater than the width W3. After the formation of the recess144, the first photoresist mask 210, shown in FIG. 8, is removed usingan ashing process or a strip process, for example.

Referring to FIG. 10, a second photoresist mask 220 is provided on thepassivation layer 142. The second photoresist mask 220 includes at leastone second opening 222 to expose a portion of the passivation layer 142below the recess 144. The formation of the second photoresist mask 220includes (1) applying a photosensitive material on the remainingpassivation layer 142 and filling in the recess 144 using a spin-coatingprocess, (2) drying the photosensitive material using a soft-bakingprocess, and (3) performing a photolithography process, includingexposing and developing processes, to remove a portion of thephotosensitive material over the conductive pad 114, thereby forming theopening 222.

Referring to FIGS. 10 and 11, at least one trench 150 penetratingthrough the passivation layer 142 and the bulk semiconductor 122 andextending into the dielectric layer 130 is created according to a stepS312 in FIG. 2. The passivation layer 142, the bulk semiconductor 122and the dielectric layer 130 are anisotropically dry-etched, using atleast one reactive ion etching (RIE) process, for example, through theopening 222 to form the trench 150, so that the width in the opening 222is maintained in the trench 150. It should be noted that the etchingprocess may utilize multiple etchants, selected based on the materialsof the passivation layer 142, the bulk semiconductor 122 and thedielectric layer 130, to sequentially etch the passivation layer 142,the bulk semiconductor 122 and the dielectric layer 130.

Referring to FIG. 11, the trench 150, communicating with the recess 144,has a width W5, less than the width W3 of the conductive pad 114 and thewidth W4 of the recess 144. The portion of the dielectric layer 136remaining below the trench 150 has a thickness T4, which is less thanhalf of a sum of the first thickness T1 and the second thickness T2 ofthe dielectric films 132 and 134. After the formation of the trench 150,an ashing process or a wet strip process may be used to remove thesecond photoresist mask 220 shown in FIG. 10, wherein the wet stripprocess may chemically alter the second photoresist mask 220 so that itno longer adheres to the remaining passivation layer 146.

Referring to FIG. 12, an isolation film 160 is deposited in the recess144 and in the trench 150 according to a step S314 in FIG. 2. Theisolation film 160 is formed on portions of the bulk semiconductor 124where the trench 150 penetrating, the dielectric layer 136 exposed bythe recess 144, and the passivation layer 146 exposed by the recess 144,but the isolation film 160 does not completely fill the recess 144 andthe trench 150. The isolation film 160, having a substantially uniformthickness, has a topology following the topology of the exposed portionsof the bulk semiconductor 124, the dielectric layer 136 and thepassivation layer 146. By way of example, the isolation film 160includes oxide, nitride, oxynitride or high-k material and can bedeposited using a CVD process, an ALD process, or the like. In someembodiments, the isolation film 160 and the dielectric layer 136 canhave the same material, but the present disclosure is not limitedthereto.

Referring to FIG. 13, a protective film 170 is deposited on theisolation film 160 according to a step S316 in FIG. 2. The protectivefilm 170, having a substantially uniform thickness, covers the isolationfilm 160, but does not fill the recess 144 and the trench 150. In orderto secure the step coverage, protective film 170 can be formed using aPVD process or an ALD process, for example, wherein the protective film170 deposited using the ALD process is highly uniform in thickness. Insome embodiments, the protective film 170 may be a single-layeredstructure including refractory metals (such as tantalum and titanium),refractory metal nitrides, or refractory metal silicon nitrides. Inalternative embodiments, the protective film 170 may comprise amulti-layered structure including one or more refractory metals,refractory metal nitrides, or refractory metal silicon nitrides.

Referring to FIGS. 14 and 15, portions of the protective film 170, theisolation film 160 and the dielectric layer 136 are removed to exposethe conductive pad 114 according to a step S318 in FIG. 2. In FIG. 14,horizontal portions of the protective film 170 are removed using ananisotropic etching process, while the vertical portions of theprotective film 170 are left on the isolation film 160, thereby forminga plurality of protective liners 172. The chemistry of the anisotropicetching process can be selective to the material of the isolation film160. In other words, no substantial quantity of the material of theisolation film 160 is removed during the etching of the horizontalportions of the protective film 170.

Referring to FIG. 15, horizontal portions of the isolation film 160 notcovered by the protective liners 172 and a portion of the dielectriclayer 136 below the trench 150 are removed to expose the conductive pad114. Therefore, a plurality of isolation liners 162 are formed. As shownin FIG. 15, at least one of isolation liners 162 includes verticalsegment 1622 parallel to the protective liners 172 and a plurality ofhorizontal segment 1624 connecting a lower end of the vertical segment1622. Referring to FIGS. 14 and 15, in some embodiments, portions of thepassivation layer 146 beneath the horizontal portions of the isolationfilm 160 can be removed simultaneous with the etching of the isolationfilm 160 if the passivation layer 146 and the isolation film 160 containthe same material. In some embodiments, the protective liners 172 areemployed to prevent the vertical segment 1622 of the isolation liner 162in the recess 142 and the vertical segment 1622 of the isolation liner162 in the trench 150 and proximal to the recess 142 from removal duringan anisotropic etching process.

Referring to FIG. 16, a diffusion barrier film 180 is deposited on theexposed portions of the conductive pad 114, the dielectric layer 136,the passivation layer 146, the isolation liners 162, and the protectiveliners 172 according to a step S320 in FIG. 2. The diffusion barrierfilm 180, having a substantially uniform thickness, has a topologyfollowing the topology of the conductive pad 114, the dielectric layer136, the passivation layer 146, the isolation liners 162, and theprotective liners 172. In order to secure the step coverage, thediffusion barrier film 180 can be formed using a PVD process or an ALDprocess, for example. The diffusion barrier film 180 may be asingle-layered structure or a multi-layered structure including one ormore refractory metals, refractory metal nitrides, or refractory metalsilicon nitrides. In some embodiments, the protective liners 162 caninclude the same material to reduce cost.

Referring to FIG. 17, a conductive material 190 is deposited to fill therecess 144 and the trench 150 according to a step S322 in FIG. 2. Theconductive material 190 is conformally and uniformly deposited on thediffusion barrier film 180 until the recess 144 and the trench 150 arecompletely filled. The diffusion barrier film 180 is employed to preventthe conductive material from flaking or spalling from the dielectriclayer 136, the passivation layer 146 and the isolation liners 162. Theconductive material 190 may include metal, such as copper, tungsten,aluminum, silver, gold, indium or the like. The isolation liners 162 areemployed to separate the conductive material 190 from the bulksemiconductor 124, thereby preventing the conductive material 190 fromdiffusion in the bulk semiconductor 124. The conductive material 190 maybe deposited using a CVD process, a PVD process, an ALD process, oranother suitable process.

Referring to FIG. 18, a planarizing process is performed to remove theconductive material 190 overflowing the recess 144. Consequently, thepassivation layer 146 is exposed and a conductive plug 192 is formed.The conductive plug 192 includes a first block 1922 disposed in thepassivation layer 146 and a second block 1924 penetrating through thebulk semiconductor 124 and the dielectric layer 136, wherein the secondblock 1924 is connected to the first block 1922 in the passivation layer146. The first block 1922 and the second block 1924 of the conductiveplug 192 have different widths. In addition, the first block 1922 andthe second block 1924 are symmetric with respect to a central axis C. Insome embodiments, the conductive plug 192 can be T-shaped when viewedfrom a cross-sectional perspective. The planarizing process can includea chemical mechanical polishing (CMP) process and/or a wet etchingprocess. The T-shaped conductive plug 192 can facilitate the bonding ofthe bump 200, as described below.

Referring to FIG. 19, a third photoresist mask 230, including at leastone opening 232, is applied on the passivation layer 146 to expose thediffusion barrier film 182 and the conductive plug 192. The thirdphotoresist mask 230 can be formed by performing an exposure process anda develop process on a photosensitive material that fully covers thepassivation layer 146, the isolation liners 162, the protective liners172, the diffusion barrier film 182, and the conductive plug 192.

Referring to FIGS. 19 and 20, at least one bump 200 is formed to atleast connect the diffusion barrier film 182 and the conductive plug192. In some embodiments, the bump 200 may further be in contact withthe protective liners 172 including refractory metal(s) and a portion ofthe passivation layer 146 exposed by the opening 232. The bump 200 canbe formed by initially placing a solder flux (not shown) on the portionsof the passivation layer 146, and the conductive plug 192 exposed by theopening 232, then disposing the bump 200 on the solder flux; once thebump 200 is in contact with the solder flux, a reflow may be performedto reflow the material of the bump 200 and the solder flux to physicallybond the bump 200 to the diffusion barrier film 182 and the conductiveplug 192.

An ashing process or a wet strip process may be used to remove the thirdphotoresist mask 230, wherein the wet strip process may chemically alterthe third photoresist mask 230 so that it no longer adheres to thepassivation layer 146. Consequently, the semiconductor assembly 10 shownin FIG. 1 is completely formed.

In conclusion, the configuration of the semiconductor assembly 10including the T-shaped conductive plug 192 and the protective liners 172can facilitate the bonding of the bump 22 and prevent metal spike,thereby enhancing reliability of the semiconductor assembly 10.

One aspect of the present disclosure provides a semiconductor assembly.The semiconductor assembly comprises a semiconductor device, a bulksemiconductor, a passivation layer, at least one conductive plug, aplurality of protective liners, and a plurality of isolation liners. Thesemiconductor device comprises at least one conductive pad. The bulksemiconductor is disposed over the semiconductor device. The passivationlayer covers the bulk semiconductor. The conductive plug comprises afirst block disposed in the passivation layer and a second blockdisposed between the first block and the conductive pad. Portions ofperipheries of the first and second blocks of the conductive plug aresurrounded by the plurality of protective liners. The plurality ofisolation liners are disposed over portions of the peripheries of thefirst and second blocks of the conductive plug.

One aspect of the present disclosure provides a method of manufacturinga semiconductor assembly. The method comprises steps of bonding a bulksemiconductor to a semiconductor device via a dielectric layer;depositing a passivation layer on the bulk semiconductor; creating atleast one recess in the passivation layer; creating at least one trenchpenetrating through the passivation layer and the bulk semiconductor andextending into the dielectric layer, wherein the trench is incommunication with the recess; forming a plurality of isolation linersand a plurality of protective liners on inner walls of the bulksemiconductor, the dielectric layer and portions of the passivationlayer exposed by the recess and the trench; removing a portion of thedielectric layer below the trench to expose at least one conductive padof the semiconductor device; and depositing a conductive material in thetrench and the recess.

Although the present disclosure and its advantages have been describedin detail, it should be understood that various changes, substitutionsand alterations can be made herein without departing from the spirit andscope of the disclosure as defined by the appended claims. For example,many of the processes discussed above can be implemented in differentmethodologies and replaced by other processes, or a combination thereof.

Moreover, the scope of the present application is not intended to belimited to the particular embodiments of the process, machine,manufacture, and composition of matter, means, methods and stepsdescribed in the specification. As one of ordinary skill in the art willreadily appreciate from the present disclosure, processes, machines,manufacture, compositions of matter, means, methods or steps, presentlyexisting or later to be developed, that perform substantially the samefunction or achieve substantially the same result as the correspondingembodiments described herein, may be utilized according to the presentdisclosure. Accordingly, the appended claims are intended to includewithin their scope such processes, machines, manufacture, compositionsof matter, means, methods and steps.

What is claimed is:
 1. A method of manufacturing a semiconductorassembly, comprising: bonding a bulk semiconductor to a semiconductordevice via a dielectric layer; depositing a passivation layer on thebulk semiconductor; creating at least one recess in the passivationlayer; creating at least one trench penetrating through the passivationlayer and the bulk semiconductor and extending into the dielectriclayer, wherein the trench is in communication with the recess; forming aplurality of isolation liners and a plurality of protective liners oninner walls of the bulk semiconductor, the dielectric layer and portionsof the passivation layer exposed by the recess and the trench; removinga portion of the dielectric layer below the trench to expose at leastone conductive pad of the semiconductor device; and depositing aconductive material in the trench and the recess.
 2. The method of claim1, further comprising depositing a diffusion barrier film on theconductive pad, the isolation liners, the protective liners, andportions of the dielectric layer and the passivation layer exposedthrough the protective liners prior to the deposition of the conductivematerial.
 3. The method of claim 2, wherein the diffusion barrier filmhas a topology following a topology of the isolation liners, theprotective liners, the portions of the passivation layer exposed by therecess, and the portions of the dielectric layer not covered by theisolation liners and the protective liners.
 4. The method of claim 1,wherein the formation of the isolation liners and the protective linerscomprises: depositing an isolation film on the passivation layer and inthe recess and the trench; depositing a protective film on the isolationfilm; removing horizontal portions of the protective film to form theprotective liners; and removing portions of the isolation film notcovered by the protective liners.
 5. The method of claim 4, whereinportions of the passivation layer not covered by the isolation linersare removed during the removal of the portion of the dielectric layerbelow the trench.
 6. The method of claim 4, wherein the portion of thedielectric layer below the trench is removed during the removal of theportion of the isolation film not covered by the diffusion barrierliners.
 7. The method of claim 4, wherein the isolation film has atopology following a topology of the bulk semiconductor, the dielectriclayer, and the portions of the passivation layer exposed by the recessand the trench.
 8. The method of claim 1, wherein the bonding of thebulk semiconductor and the semiconductor device comprise: depositingdielectric films on the semiconductor device and the bulk semiconductor;mounting the semiconductor device onto the bulk semiconductor so thatthe dielectric films are in contact; and performing an anneal process tofuse the dielectric films, thereby forming the dielectric layer.
 9. Themethod of claim 1, wherein after the formation of the trench, athickness of the dielectric layer below the trench is less than half ofa thickness of the dielectric layer connecting the bulk semiconductor tothe semiconductor device.
 10. The method of claim 1, wherein theconductive pad has a first width, the recess has a second width lessthan the first width, and the trench has a third width less than thefirst and second widths.
 11. The method of claim 1, further comprisingperforming a grinding process to thin the bulk semiconductor prior tothe deposition of the passivation layer.
 12. The method of claim 1,further comprising: performing a planarizing process to remove a portionof the conductive material overflowing the recess; and forming at leastone bump on the conductive material after the planarizing process.